Process of refining hydrocarbon oils



Patented Mar. 17, 1931 UNITED STATES PATENT OFFICE ALEXANDER S. RAMAGE, F DETROIT, MICHIGAN, ASSIGNOR TO GYRO PROCESS COM- PANY, OF DETROIT, MICHIGAN,

A CORPORATION OF MICHIGAN PROCESS OF REFINING HYDROCARBON OILS No Drawing.

This invention relates to a process for refining or purifying hydrocarbons or mixtures such as the aromaticfolefine andnaphthene hydrocarbons which dissolve or are soluble in or capable of forming homogeneous liquid mixtures with alcohol and has particular reference to the treatment of such hydrocarbons and mixtures with alcoholic caustic alkali for the removal of sulfur or chlorine or both sulfur and chlorine compounds therefrom. The invention is based upon the idea of using a mutual solvent for the hydrocarbon and the refining agent and the process of the invention which involves the use of alcohol as the mutual solvent, therefore, is not applicable for the treatment of parafiin hydrocarbons with which alcohol is not miscible to any appreciable extent.

In order that the invention may be clearly understood, it is said that it has been customary heretofore in refining hydrocarbon oils such as crude benzol, mineral lubrieating 011, gasoline, kerosene and the like to treat the oil first with sulfuric acid or with chlorine or hypochlorite and then to treat the oil with an aqueous solution of a caustic alkali. It has been found, however, that oils refined in this manner still retain a quantity of sulfur or chlorine. When the oils are subjected to a sufficiently high temperature in the presence of metals, for instance, when they are used as fuel or as lubricant or subjected to distillation, these impurities exert a corrosive action upon the metals.

I have now found that by the use of alcoholic caustic alkalis for the treatment of those hydrocarbons above referred to in which alcohol is soluble the objectionable sulfur or chlorine compounds are removed. The treatment with alcoholic caustic alkali may be applied at any suitable stage of the refining of the hydrocarbons, for instance, it may be applied directly to any hydrocarbon of Lthe type referred to with which alcohol is miscible re ardless of its source or it may be applied a er a preliminary refining of the hydrocarbon, for instance, after a preliminary treatment of the hydrocarbon with aqueous caustic alkali. The employment of Application filed August 27, 1926. Serial No. 132,047.

a preliminary treatment of the hydrocarbon with aqueous caustic alkali in order to reduce the alcoholic caustic alkali requirements ordinarily is preferred, particularly when the hydrocarbon to be treated contains relatively large amounts of impurities. It is, of course, apparent that the alcoholic caustic alkali treatment may also serve to remove inipurities other than sulfur and chlorine compounds, if present in the hydrocarbon, such as for instance resin or gum forming constltuents.

The treatment with alcoholic caustic alkali may consist simply in mixing the hydrocarbon and the alcoholic caustic alkali and permitting the mixture to stand with occasional agitation, if desired, until the desired reaction is complete and then separating the treated oil from the mixture and washing the separated hydrocarbon with water to remove residual alcoholic caustic alkali therefrom. Treatment in this manner ordinarily requires from 10 to 12 hours. The treatment may be considerably hastened by heating the mixture to say 70 C. or even higher in a closed digestor under pressure, if necessary, or under a reflux condenser to prevent loss of volatile constituents of the mixture. In this Way the treatment may be completed in as short a time as 2 to 3 hours or even less.

The mixture of the hydrocarbon and the alcoholic caustic alkali formed by either of the two methods described above, upon standing stratifies into two liquid layers, to-wit, an upper layer of-clear oil and a lower layer of alcoholic caustic alkali usually of a dark brown color due to the impurities extracted from the oil. The two layers are separated, for instance, by decantation, the oil layer is washed with water in the well known manner, and may then be dried, distilled or further treated in any suitable manner. It is, of course, understood that the settling of the mixture may be hastened, if desired, by centrifugal action.

The strength and quantity of alcoholic caustic alkali used in the treatment of differ ent hydrocarbons is quite variable depending upon the purity of the hydrocarbon treated and other practical considerations. I prefer ordinarily to use an alcoholic caustic alkali solution containing about 10% ofthe caustic alkali. The alcohol used may be either ethyl alcohol or methyl alcohol or mixtures of the two or what is commonly known as industrial alcohol and should be relatively free of water, that is, it should contain not more than about 2% of water, since the solubility of alcohol in hydrocarbons of the character referred to is considerably reduced by the presence of water. The quantity of a 10%solu- ,tion of caustic alkali in alcohol to be used in the treatment of a hydrocarbon ordinarily lies within the range of 2 to 5 parts by volume of the alcoholic caustic alkali to 100 parts by volume of the hydrocarbon. As the caustic alkali either caustic soda or caustic potash may be used, the former being preferred'on account of its lower cost.

The following examples illustrate the process:

I. 1000 gallons of a mixture of olefine and naphthene hydrocarbons, such as the product roduced in accordance with my United rtates Letters Patent No. 1,403,194, after being treated in the usual manner with sulfuric acid followedby washing with water is mixed "stratify and the upper with about 30 gallons of 10% alcoholic caustic soda and the mixture is heated for about 2 hours to a temperature of about 70 C. in a still provided with a reflux condenser or in a closed digestor or the mixture is simply allowed to stand after thorough agitation at atmospheric temperature for about 10'hours. In either case the mixture is permitted to hydrocarbon layer s separated from the lower alcoholic caustic soda layer and washed with water in the well known manner. The resulting washed hydrocarbon which may be further refined as described is practically free of sulfur.

'II. Crude benzol after a single treatment with sulfuric acidin the usual way is mixed with about 2% by volume of a 10% alcoholic caustic soda solution and the mixture digested as described in Example I after which the benzol is separated and washed with water. The resulting benzol is practically free of thiophenes which cannot normally be removed excepting by a plurality of treatments with sulfuric acid.

This application contains subject matter in common with my application Ser. No. 701,209, filed March 22, 1924.

I claim:

1. A method of removing sulfur and chlorine from such hydrocarbons as are soluble'm alcohol which comprises mutually dissolving such hydrocarbons in an alcoholic solution of an alkali metal hydroxide, permitting the solution to stratify, and separately removing I the purified oil and the alcoholic/alkaline solution-containing the impurities.

2. A method of removing sulfur and chlorine from aromatic, olefine and naphthene 3. A method of removing sulfur and chlorine from suchhydrocarbons as are soluble in alcohol and which have been submitted to a preliminary treatment with an agent of the group comprising sulfuric acid and active chlorine compounds which comprises mutually dissolving such hydrocarbons in an alcoholic solution of an alkali metal hydroxide, permitting the solution to stratify, and separately removing the purified oil and the alcoholic alkaline solution containing. the impurities.

4. A method of removing sulfur and chlorine from aromatic, olefine and napthene hydrocarbons, and mixtures thereof, which have been submitted to a preliminary treatment with an agent of the group comprising sulfuric acid and active chlorine compounds which comprises mutually dissolving such hydrocarbons in an alcoholic solution of an alkali metal hydroxide, permitting the solut1on to stratify, and separately removing the purlfied oil and the alcoholic alkaline solut1on containing the impurities.

In testimony whereof, I afiix my signature.

ALEXANDER S. RAMAGE. 

